When something is noticeable in psychology it is observable.
Behaviour can either be psychological or physical.
If you touch your hand on a hot stove, then the behaviour that results when you withdraw your hand is physical.
However, if you are afraid of germs, and you accidently touch something you consider to be germy, then the behaviour of withdrawing your hand is psychological.

possibly - at least it would be fairly neutral (or at least restrained) in tone

All behaviour that isn't pure physical reflex indicates something about the psychology of the subject. I haven't a clue what "auffällig" means, as I don't know German. However, I assume from the context you give in English that they are trying to identify some shared psychological basis of whistleblowing.

I am familiar with German, but not really conversant. But this might fit with the German idea.

"The suit portrays Dumas as an outspoken
whistleblower who was unjustly fired."
http://www.statesmanjournal.com/fdcp/?1274992733103

"Cathy Harris, an outspoken critic against the
Department of Homeland Security was
terminated from Customs on May 1, 2005 for
filing discrimination complaints and blowing
the whistle in 1999."
http://www.thecathyharrisstory.com/Cathy_Harris_Story_Wins_P...

Mother’s outspoken behavior on these issues did not endear her to the church and school leaders, as well as many parents. She was, however, a hero to me, and to the girls. But, nothing was done to stop the sexual harassment of young girls by powerful church and religious school leaders. They did keep their distance from me, though, because of my mom. Sometimes a girl – or boy -- needs a “helicopter parent” when there are predators like that lurking and waiting to prey on the very young people they are charged to educate and protect.
http://community.nytimes.com/comments/thelede.blogs.nytimes....

Frühling will be missed. Without ever being accused of “combative” or “outspoken” behavior, he became known for firmly but diplomatically calling “foul” in the face of the Uribe government’s frequent human rights lapses.
http://www.ciponline.org/colombia/blog/archives/cat_human_ri...

It may be because, by standing up for the rights of the targeted child, these defenders have called attention to the bully's inner character problems, thus adding insult to injury in the bully's calculations. Their outspoken behavior challenges the bully's right to harm others.
http://www.learningdisabilitiesinfo.com/bullied-children.htm...